Project Summary/Abstract Current interest in redesigning primary care through the Patient-Centered Medical Home presents an important opportunity to change patient care, especially for those primary care patients with mental health diagnosis in addition to or as part of their other medical problems. The state of Colorado, and the team assembled to create a Cost Assessment of Collaborative Healthcare (CoACH), are all committed to better understanding how to help primary care continue its transformation through better mental health integration. As more primary care practices begin to consider integration, being able to calculate the cost of the model and transformation (both direct and indirect) will become paramount. This proposal offers a unique lesson to learn about the cost of mental health integration with primary care. To date, only the most researched of models have examined the role of cost, and have predominately examined the cost-offset and cost-effectiveness of the intervention model. If models of integration are to proliferate more throughout healthcare, there must first be a more comprehensive understanding of their costs in the larger context of healthcare transformation.